The Interpretation Model - Models and Methods of Magnetotellurics - page 386

Fig. 11.12 Combined graph of the apparent-resistivity and impedance-phase curves obtained in
the model of the -effect shown in Fig. 11.11

eff over each
zone, we get a visibly consistent and geophysically meaningful pattern. The result
of the trial one-dimensional inversion of the average ˆ

approximated by the log-normal low (solid line).When averaging log

curves is presented in
Fig. 11.17. On the Siberian platform we find a deep conductive layer with resistivity
of 100-200 Ohm

eff −

m at a depth from 25 to 40 km. Approaching the Baikal rift, the
crustal layer rises and its resistivity diminishes. In the Trans-Baikal zone the depth
to the conductor reaches 15 km, whereas the resistivity reduces to 10-15 Ohm

·

m.
So, even at this rough level, we gain an insight into geoelectric structure of the
Baikal rift.

·

11.1.3 Filtering Apparent Resistivities

Generally the spatial spectrum of magnetotelluric responces functions
(impedances, apparent resistivities) consists of high frequencies characterizing
the

non-interpretable geoelectric noise produced by small-scale near-surface